Methods, devices and compositions for depositing and orienting nanostructures

ABSTRACT

Methods and systems for depositing nanomaterials onto a receiving substrate and optionally for depositing those materials in a desired orientation, that comprise providing nanomaterials on a transfer substrate and contacting the nanomaterials with an adherent material disposed upon a surface or portions of a surface of a receiving substrate. Orientation is optionally provided by moving the transfer and receiving substrates relative to each other during the transfer process.

BACKGROUND OF THE INVENTION

Nanotechnology has been heralded as the next major technological leap,in that it is prophesied to yield a variety of substantial advantages interms of material characteristics, including electronic, optical andstructural characteristics. Some have predicted that advances innanotechnology are the best hope for extending the lifespan of Moore'slaw.

While nanotechnology advances have produced materials with myriadinteresting properties with broad potential applicability, theintegration of these materials into useful devices, systems andmaterials has remained somewhat of a stumbling block when viewed fromthe perspective of commercial manufacturability. By way of example,carbon nanotubes, often viewed as the hallmark of nanomaterials, arelargely unusable from a commercial standpoint as anything more thanfiller for composite materials, e.g., to impart structural, and perhapscrude electrical properties to the overall bulk composite. This isbecause these nanotubes often have unpredictable electrical propertiesfrom one nanotube to the next, requiring a sensitive selection processin order to be able to use them reproducibly for more exactingrequirements, e.g., in electronics, etc.

Another difficulty that affects virtually all nanomaterials is theintegration of these materials into devices and/or systems whereplacement of such materials is important, e.g., bridging electricalcontacts, spanning gate electrodes, etc. In particular, these materialsare so small that it is virtually impossible to accurately position themusing manual manipulative techniques, particularly from a commercialmanufacturing standpoint, e.g., in large quantities with high yields. Anumber of methods have been proposed and demonstrated for positioning ofthese materials using more manageable methods. For example, flowdirected placement methods have been successfully utilized to direct andplace semiconductor nanowires in desired locations, e.g., wheresolutions containing wires or nanotubes are flowed into contact withsubstrates to both align, via the flow, and place, via the contactregions, wires onto the substrate surface. Molecular recognition andself assembly techniques, e.g., using chemical groups on the desiredlocations of the substrates and complementary groups on thenanomaterials, have also been proposed and demonstrated for theplacement of nanomaterials in desired locations of substrates. Despitethe reported effectiveness of these methods in positioningnanomaterials, to date such methods have yielded widely disparateresults, e.g., in the uniformity of the deposition, orientation andpositioning of the materials. The lack of uniformity is very detrimentalin a commercial manufacturing setting, particularly when applied to,e.g., the electronics industry where product to product variations mustbe virtually non-existent. These methods also suffer from manufacturingrequirements that will require substantial infrastructure development aswell as development of an “art” form in the performance of thesetechniques.

Accordingly, there exists a need for a robust, repeatable process forthe positioning and/or orientation of nanomaterials on other substratematerials for use in, e.g., electronics, optoelectronic, optical andmaterial applications. The present invention meets these and a varietyof other needs.

BRIEF SUMMARY OF THE INVENTION

The present invention generally provides methods, compositions, systemsand the like for positioning and optionally orienting or aligningnanostructures onto a surface of a substrate, typically for integrationinto a functional device or composition.

In particular, in a first general aspect, the invention provides amethod of depositing nanomaterials onto a substrate. In accordance withthe invention, a plurality of nanostructures are provided disposed upona transfer substrate. An adherent material is provided deposited onselected regions of a receiving substrate. The transfer substrate ismated with the receiving substrate whereupon the nanostructures contactthe nanostructures on the transfer substrate with the selected regionsof the receiving substrate. When the transfer substrate is separatedfrom the receiving substrate it leaves nanostructures adhered to theselected regions of the receiving substrate.

In a related aspect, the deposited nanostructures are substantiallyoriented during the deposition process by moving one or more of thetransfer substrate and receiving substrate relative to the other of thetransfer substrate and the receiving substrate to substantially orientthe nanostructures along a common axis. The nanostructures are thenseparated from the transfer substrate after the moving step, to leavethe plurality of nanostructures substantially oriented on the receivingsubstrate along the common axis.

The invention also provides articles that have a first substrate havingan adherent material disposed upon its surface and a plurality ofnanostructures disposed upon the adherent material, and optionallysubstantially oriented along a common axis. Similarly, the inventionprovides compositions that comprise a layer of polymeric adherentmaterial with a plurality of substantially aligned nanowires adhered toa surface of the adherent layer.

A number of uses, applications and variations to the invention will bereadily apparent from the following disclosure, and are generallyencompassed within the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of the nanostructure depositionprocesses of the invention.

FIG. 2 is a schematic illustration of a nanowire based electronicdevice, e.g., a transistor.

FIG. 3 is a schematic illustration of a transistor array and individualdevice made using oriented populations of nanowires as the conductivechannel for the device.

FIG. 4 is a schematic illustration of the nanostructure deposition andalignment/orientation methods of the invention.

FIG. 5 is a schematic illustration of a roll-roll process for producingnanowire substrates in relatively high volume.

FIG. 6 is a SEM image of semiconductor nanowires deposited and orientedon a silicon wafer substrate in accordance with the invention.

DETAILED DESCRIPTION

The present invention is generally directed to devices, systems andmethods for use in positioning and/or orienting nanomaterials, andparticularly nanomaterials having high aspect ratios onto othersubstrate materials. In general terms, the invention involves thetransfer of nanomaterials from a first substrate, also termed a“transfer substrate” to a second substrate upon which it is desired toposition such nanomaterials, also termed a “receiving substrate.” Thus,initially, the nanomaterials are provided upon a surface of the transfersubstrate. The transfer is effected by providing an adherent materialdeposited upon a surface of the receiving substrate upon which thenanomaterials are desired to be deposited, positioned and/or oriented.The nanomaterials on the transfer substrate are then contacted with theadherent material on the receiving substrate to affix the nanomaterialsonto the receiving substrate, by contacting the two substrate surfacestogether.

Once the two substrates are separated, nanomaterials that contact theadherent material on the receiving substrate are lifted from thetransfer substrate and transferred to those portions of the receivingsubstrate that include the adherent material. By controlling thelocation of the adherent material on the receiving substrate, one caneffectively pattern or position the nanomaterials in desired regions ofthe receiving substrate, while leaving other regions of the receivingsubstrate clear of the nanomaterials. Further, by controlling thecontacting and separating steps, one can also control, to a largeextent, the orientation and/or configuration of the nanostructures thusdeposited. As will be apparent from the following disclosure, a widevariety of variations, modifications and improvements upon the basicinvention may be practiced.

FIG. 1 provides a schematic illustration of the processes employed inthe present invention. As schematic representations, the illustrationsare presented solely for the purpose of clarifying certain aspects ofthe invention and are not intended as “to scale” or detailedrepresentations of any aspect of the invention, nor should they beviewed as providing any limitations on the invention. As shown in panelA, a first substrate, e.g., transfer substrate 102, is provided havingnanostructures, e.g., nanowires 106, disposed on its surface 104. Asecond, or receiving substrate 108 is provided. Upon the surface 110 ofthe receiving substrate 108, where nanostructure deposition is desired,an adherent material or surface treatment 112, is provided. As shown inPanel B, the two substrates are brought together whereby thenanostructures 106 contact the adherent surface 112, on the receivingsubstrate 108, so that at least a portion of the nanostructures 106adhere to the adherent surface 112 of the receiving substrate. Uponseparation (See Panel C) of the two substrates, the nanowires 106 aretransferred to the adherent surface 112 on the receiving substrate 108.

As described above, true nanomaterials, e.g., structural materialshaving at least one cross sectional dimension of less than 500 andpreferably less than 100 nm, possess a wide variety of interestingproperties, including electrical properties, optoelectronic properties,optical properties and structural properties. While certain of theseproperties can be exploited in bulk applications, e.g., the structuralcharacteristics of nanomaterials incorporated into composites, a muchlarger number of useful applications require some measure of precisionin the positioning, configuration and orientation of the nanomaterials.Issues relating to the configuration of the nanomaterials have been atleast partially addressed through novel synthetic schemes whereby onecan produce very well defined populations of zero and one dimensionalnanomaterials. High aspect ratio nanomaterials, e.g., nanorods,nanowires and nanotubes, are particularly useful for a number ofelectronic and optoelectronic applications. For ease of discussion, allof these high aspect ratio nanomaterials are referred to genericallyherein as nanowires. Further, despite the primary focus on high aspectratio nanomaterials, it will be appreciated that many aspects of thepresent invention are equally applicable to positioning of lower aspectratio nanomaterials onto a receiving substrate, e.g., spherical or nearspherical nanocrystals, e.g., quantum dots.

High aspect ratio semiconductor nanomaterials have particularly valuableproperties when employed in electronic applications and particularlylarge area or “macroelectronic” applications. In particular, becausesemiconductor nanowires generally have a single crystal or near singlecrystal structure, they possess relatively high electron mobilities allalong their length dimension that are generally on the same order as themobilities found in single crystal silicon substrates. However, becausethey are free standing structures, they can be processed in a much morecost effective fashion than slabs of single crystal semiconductors, morelike amorphous semiconductors (whose electron mobilities are too low formany applications). Similar to amorphous semiconductors, these nanorodsand nanowires are also amenable to processes that yield flexibleelectronics. The use of nanomaterials, and particularly semiconductornanowires in these applications has been described in substantial detailin, e.g., U.S. Provisional Patent Application Nos. 60/414,323 and60/414,359, each filed Sep. 30, 2002, and 60/468,276, filed May 7, 2003,the full disclosures of which are hereby incorporated herein byreference in their entirety for all purposes.

In general, producing electronic components from nanowire materials,e.g., thin film transistors (TFTs) or the like, typically involvesdepositing the nanowires or nanorods onto a substrate material so thatthe nanowires make appropriate contact with other electrical componentsof the device that is being fabricated, e.g., providing a conductivepath between source and drain electrodes. FIG. 2 schematicallyillustrates the use of nanowires as electronic components. Inparticular, shown is a simple nanowire transistor device 200 thatincludes a nanowire 202 that connects two electrodes, e.g., sourceelectrode 204 and drain electrode 206, all disposed upon a basesubstrate 210. In the case of a field effect transistor, a gateelectrode 208 is provided adjacent the nanowire to modulate theconductivity of the nanowire 202. Although illustrated and described asa transistor, it will be appreciated that a large variety of electricaldevices may be produced that include the basic nanowire structure,including basic transistors, MOSFETS, MESFETS, intra and inter-wirediodes, etc. As will be appreciated, by orienting the nanowires duringthe deposition process, one can substantially improve the yield of theprocess used for fabricating devices, e.g., by ensuring all necessarycontacts are made between electrodes.

In a modified application of the nanowire electronics shown in FIG. 2,large numbers of nanowires can be used, e.g., as a film, to provideelectronics with enhanced properties, such as ease of fabrication oflarge area electronics, e.g., as illustrated in transistor array 300,and relatively high performance. In particular, as can be seen in panelA, a large area macroelectronic device, array or substrate, e.g., array300, is produced using populations of nanowires disposed over thesurface of the substrate or portions thereof. In this array, individualdevices, e.g., transistor 302, can further take advantage of the highaspect ratio of these nanowire materials by including large numbers oforiented wires that substantially span the space between two or moreelectrodes. In particular, Panel B illustrates a simplified electroniccircuit device from array 300, using large numbers of oriented nanowires304 deposited upon a substrate surface 306 as the semiconductive channelbetween two electrodes, e.g., source electrode 308 and drain electrode310. By so orienting these materials, one can effectively provide singlecrystal semiconductor electron mobilities between the electrodes, e.g.,in individual wires, while providing sufficient current density (e.g.,through multiple wires) with extremely low lateral electron mobilities,e.g. orthogonal to the direction from one electrode to another. Further,as noted above, the overall small scale of the individual nanowires inboth length and width dimensions, allows for production of flexibleoverall electronic devices using simplified processing technologies. Asshown, the transistor 302 also includes gate electrode 312. Fabrication,application and performance of devices like that schematicallyillustrated in FIG. 3 are described in substantial detail in, e.g., U.S.Patent Application Nos. 60/414,323 and 60/414,359, each filed Sep. 30,2002, 60/468,276, filed May 7, 2003, ______ (Attorney Docket No.01-001700) filed Aug. 7, 2003, 60/445,421 filed Feb. 5, 2003,60/474,065, filed May 29, 2003 and ______ (Attorney Docket No.01-002900) filed Jul. 22, 2003, the full disclosures of which are herebyincorporated herein in their entirety for all purposes.

Typically, the nanowires employed in electronics applications areproduced by growing or synthesizing these elongated structures on planarsubstrate surfaces. By way of example, Published U.S. patent applicationNo. US-2003-0089899-A1 discloses methods of growing uniform populationsof semiconductor nanowires from gold colloids adhered to a solidsubstrate using vapor phase epitaxy. Greene et al. (“Low-temperaturewafer scale production of ZnO nanowire arrays”, L. Greene, M. Law, J.Goldberger, F. Kim, J. Johnson, Y. Zhang, R. Saykally, P. Yang, Angew.Chem. Int. Ed. 42, 3031-3034, 2003) discloses an alternate method ofsynthesizing nanowires using a solution based, lower temperature wiregrowth process. A variety of other methods are used to synthesize otherelongated nanomaterials, including the surfactant based syntheticmethods disclosed in U.S. Pat. Nos. 5,505928, 6225,198 and 6,306,736,for producing shorter nanomaterials, and the known methods for producingcarbon nanotubes, see, e.g., US-2002/0179434 to Dai et al. As notedherein, any or all of these different materials may be employed in theprocesses, devices and systems of the invention. For semiconductorapplications, a wide variety of type III-V, II-VI and IV semiconductorsmay be utilized, depending upon the ultimate application of the deviceproduced. In general, such semiconductor nanowires have been describedin, e.g., US-2003-0089899-A1, incorporated herein above. Similarly,semiconductor nanorods and quantum dots have also been reportedfabricated from any number of different type III-VI, III-V and IVsemiconductors. In certain preferred embodiments, the nanowires areselected from a group consisting of: Si, Ge, Sn, Se, Te, B, Diamond, P,B—C, B—P(BP6), B—Si, Si—C, Si—Ge, Si—Sn and Ge—Sn, SiC, BN/BP/BAs,AlN/AlP/AlAs/AlSb, GaN/GaP/GaAs/GaSb, InN/InP/InAs/InSb, BN/BP/13As,AlN/AlP/AlAs/AlSb, GaN/GaP/GaAs/GaSb, InN/InP/InAs/InSb,ZnO/ZnS/ZnSe/ZnTe, CdS/CdSe/CdTe, HgS/HgSe/HgTe, BeS/BeSe/BeTe/MgS/MgSe,GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr,Cul, AgF, AgCl, AgBr, AgI, BeSiN₂, CaCN₂, ZnGeP₂, CdSnAs₂, ZnSnSb₂,CuGeP₃, CuSi₂P₃, (Cu, Ag)(Al, Ga, In, Tl, Fe)(S, Se, Te)₂, Si₃N₄, Ge₃N₄,Al₂O₃, (Al, Ga, In)₂(S, Se, Te)₃, Al₂CO, and an appropriate combinationof two ore more such semiconductors.

In various aspects, the at least one semiconductor may optionallycomprise a dopant from a group consisting of: a p-type dopant from GroupIII of the periodic table; an n-type dopant from Group V of the periodictable; a p-type dopant selected from a group consisting of: B, Al andIn; an n-type dopant selected from a group consisting of: P, As and Sb;a p-type dopant from Group II of the periodic table; a p-type dopantselected from a group consisting of: Mg, Zn, Cd and Hg; a p-type dopantfrom Group IV of the periodic table; a p-type dopant selected from agroup consisting of: C and Si.; or an n-type is selected from a groupconsisting of: Si, Ge, Sn, S, Se and Te.

In addition to single crystal nanowires, in certain aspects, nanowireheterostructures may be employed in the invention, e.g., longitudinal orcoaxial heterostructures, if the end application of the device dictates.Such coaxial and longitudinal heterostructured nanowires are describedin detail in, e.g., Published International Patent Application No. WO02/080280, which is incorporated herein by reference for all purposes.

While generally described in terms of inorganic semiconductor materials,it will be appreciated that the deposition and alignment techniquesdescribed herein, may be used to dseposite and/or orient anynanomaterial, and for purposes of the orientation aspects of theinvention, any elongate nanomaterial, e.g., nanorods, carbon nanotubes,polymeric nanofibers, organic or inorganic nanofilaments, proteinnanofibrils, etc.

In accordance with the present invention, the nanowires are provideddisposed on a surface of a transfer substrate, and preferably, areadhered to the surface of the transfer substrate. For purposes of theinvention, the transfer substrate may comprise the substrate upon whichthe nanowires are synthesized, e.g., using a colloid based method, or itmay comprise a different substrate. For example, in a first aspect, thetransfer substrate comprises the substrate upon which the nanowires aregrown or synthesized. In particular, for a number of methods ofproducing nanowires, a particle or colloid, e.g., a gold colloid, isdeposited on a substrate surface, and is used to seed the growth ofsemiconductor nanowires using vapor phase epitaxial growth. Theresultant nanowires are tethered to the surface of the substrate byvirtue of their having been synthesized upon it. For a discussion ofsuch wire synthesis, see, e.g., US-2003-0089899-A1.

In alternative aspects, nanowires may be produced elsewhere from thetransfer substrate and subsequently deposited upon the transfersubstrate. For example, nanowires may be produced upon and harvestedfrom a growth substrate. The free nanowires, e.g., typically disposed ina fluidic suspension for ease of handling, are then deposited upon atransfer substrate surface. Deposition of nanowires onto the surface ofthe transfer substrate may be accomplished by a number of means. Forexample, the fluid suspension of nanowires may be coated onto thesurface using, e.g., spin coating methods, or they may simply be flowedover the surface, and subsequently fixed to the surface of the transfersubstrate. Fixing of the nanowires to the surface of the transfersubstrate may be accomplished by taking advantage of natural forcesbetween the nanowires and the surface, e.g., Van der Waals forces, or byincorporating a functional layer on the surface of the substrate and/orwires to enhance adhesion, e.g., a chemical binding layer, i.e.,polylysine, polybrene, a silane or other oxide coating on the surface,etc. For a discussion of adherents useful for affixing nanowires to thesurface of a substrate, e.g., a transfer substrate, see, e.g., U.S.patent application Ser. No. 10/405,992, filed Apr. 1, 2003, andincorporated herein by reference in its entirety for all purposes.

Alternatively, one may use the same adherent materials described indetail below for affixing the nanowires to the receiving substrate,provided that they are appropriately formulated on the transfer andreceiving substrates to permit transfer of the nanomaterials from theformer to the latter.

As noted a transfer substrate may comprise virtually any material. Forexample, in the case of a transfer substrate upon which the nanowiresare grown, the transfer substrate may comprise a solid, rigid substrate,e.g., a silicon wafer, glass plate, polymeric plate, ceramic plate, orthe like. Alternatively, it may comprise a flexible material, e.g., aflexible foil, e.g., aluminum, gold or the like, or a flexible polymericsheet, provided that the flexible material is compatible with thenanowire synthesis process. For instances where the transfer substrateis an intermediate substrate, e.g., a substrate upon which the nanowiresare deposited after being fabricated, then such substrate can comprisevirtually any suitable material, e.g., suitable of being manipulated inaccordance with the ultimate process and suitable for receiving thenanowires and having them adhered thereto. In particularly preferredaspects, transfer substrates upon which the nanostructures arefabricated may comprise any suitable substrate material for suchmanufacture. For example, for nanowires or other structures produced byrelatively high temperature CVD or other vapor phase synthetic methods,the substrate may include a solid silica or other semiconductor basedsubstrate like silicon or glass, or any other substrate surfaces thatare used in this method.

Alternatively, transfer substrates upon which pre-synthesized wires aredeposited, may be comprised of any number of different materials,including those solid substrates described above, as well as moretemperature or chemically sensitive substrates, such as polymer films,or other organic materials.

In some cases, the nanostructures may be pre-oriented on the transfersubstrate so as to transfer the structures to the receiving substrate ina substantially aligned or oriented state, e.g., the structures on thereceiving substrate are substantially oriented as described herein.Orientation of nanostructures on the transfer substrate may beaccomplished by a number of methods. For example, the structures may be“combed” into alignment or orientation. Such combing may comprisecontacting the structure bearing substrate with a physical structure,e.g., a straight edge or surface, that is dragged across the structuresto shear align those structures. Alternatively, a fluid based method maybe employed where fluid is flowed over the structure bearing surface toflow align the structures that are attached to that surface. In otheraspects, the structures may be produced in a pre-aligned orientation.For example, aligned growth of nanowires has been previously describedin, e.g., U.S. patent application Ser. No. 10/405,992, which isincorporated herein by reference in its entirety for all purposes.Further, while described in terms of aligning nanostructures on atransfer substrate, it will be appreciated that such alignment may beapplied to the nanostructures on the receiving substrate, post transfer.

In addition to simply transferring nanowires from a transfer substrateto a receiving substrate, the present invention also provides in certainaspects for specific positioning and/or alignment of the wires that aretransferred onto the receiving substrate. For example, by providing theadherent material or surface treatment to selected portions of anoverall substrate, one can select precisely where nanostructures, e.g.,nanowires will be transferred/disposed upon that substrate. For example,with reference to FIG. 3, one can position the nanowires on selectedportions of the overall receiving substrate surface 306, by providingadherent material patterned onto the substrate in only selected regions,e.g., region 314 (as shown by the staggered outline box). Patterning ofthe adherent surface is readily accomplished by any number ofconventionally available technologies. For example, selected regions maybe coated with adherent materials using physical masking methods, or maybe patterned from photoresists using conventional photolithographytechniques.

In general, the invention affects alignment of transferred nanowires byshifting the transfer substrate or receiving substrate relative to theother while the nanowires are contacting and adhered to the surface ofthe receiving substrate but not yet separated from the transfersubstrate. In particular, once the transfer substrate having thenanowires disposed thereon is contacted with the receiving substratesurface bearing the adherent material, one of the transfer substrate orreceiving substrate is moved relative to the other to align thenanowires in the direction of that movement, e.g., by pulling the wiresinto alignment. When the substrates are separated, the depositednanowires are disposed in a substantially aligned orientation.

By “substantially aligned orientation” means that a majority of thenanostructures in a population of nanostructures is predominantlyoriented substantially along a given axis, which means that thealignment of such structures in the majority of the population have anorientation that does not vary from the given axis by more than 30degrees, preferably not more than 20 degrees, and in many cases variesless than 10 degrees or even 5 degrees from the given axis.

Typically, the relative movement of one substrate to another is in therange of the length of the average nanowires being deposited andaligned, and typically less. As such, the substrates will typically bemoved relative to each other by up to 5 mm (from the position of initialcontact). In many cases, smaller movements may be made, e.g., shiftingthe substrates relative to each pother by no more than 1 mm, 100 μm, 10μm or 1 μm or even less than 1 μm. In some cases, higher depositednanowire or nanostructure densities may be accomplished by providinggreater drag distances over a substrate, or by repeating shorterdragging steps, interspersed with separation and re-contacting steps, todeposit more nanowires or other nanostructures in a single location.

In general, instrumentation is readily available to perform themanipulation operations described herein, including precisiontranslation stages, micromanipulators, etc. In the case of roll to rolltransfer movement of one substrate relative to the other may be affectedby varying the speeds of one substrate roll relative to the other, e.g.,moving one substrate slightly slower than the other, so that nanowirescontacting the receiving substrate are pulled into alignment in thedirection of the differential speed.

FIG. 4 schematically illustrates the combined transfer and alignmentprocesses of the invention. Briefly, the transfer substrate 402 bearingthe nanowires 406 is contacted with the adherent surface 412 (See panelsA and B) of the receiving substrate 408, whereupon the wires are adheredto that surface (see panel B). Prior to separating the two substrates,one or both of the transfer 402 and receiving 408 substrates is movedrelative to the other, e.g., as shown by the arrows in panel C, to pullthe wires into alignment in the direction of relative movement.Following such alignment, the substrates are separated to leavesubstantially aligned nanowires 414 disposed on the surface of thereceiving substrate 408. Again, although the foregoing processes aredescribed in terms of depositing aligned nanostructures on a receivingsubstrate, it will be appreciated that the such a receiving substrate incertain cases, may be used as a transfer substrate, e.g., one may usethe alignment and deposition processes described above to provide forpre-alignment of the nanostructures for a subsequent transfer step,e.g., to transfer pre-aligned or oriented nanostructures to anadditional receiving substrate.

In the case of an intermediate transfer substrate, e.g., where atransfer substrate is other than, it may be desirable to treat such anintermediate substrate so as to enable easy removal of thenanostructures from the transfer substrate e.g., to transfer them to thereceiving substrate. By way of example, the transfer substrate surfacemay be chemically treated to provide poorer adhesion to thenanostructures than the receiving substrate, thus providing easytransfer. Examples of such treatments include, e.g., coatings ofnon-stick materials, e.g., Teflon or other organic coating materials.Similarly, chemical treatments may be provided that provide an activatedrelease, e.g., a photo, chemical or thermally cleavable chemical linkergroup that binds the nanostructure to the transfer substrate. Uponcontact with the receiving substrate (or prior to such contact), theactivatable group is activated to release the nanostructures and alloweasy transfer. Other reversible linking or coupling techniques mightalso be employed for coupling nanostructures to a transfer substrate,including, e.g., using electrostatic, or magnetic forces to maintain thenanostructures on the transfer substrate until the transfer is desired.

As with the transfer substrate, the receiving substrate, too, may becomprised of virtually any material that suits the needs of the ultimateapplication of the devices fabricated therefrom. For example, certainapplications may require rigid substrates that have a high degree oftolerance to extremes of heat, chemical agents or the like. In stillother applications, the ultimate device may benefit from being flexible,transparent, thin or from having a number of other characteristics thatmay be imparted by the underlying substrate, e.g., low cost, or lowglass transition temperature (Tg). For antenna applications, forexample, materials with good RF performance characteristics will bepreferred, e.g., high or controlled dielectric constants, low loss, wellcontrolled thickness, etc. Similar characteristics may be useful forstacked or layered circuits or for mass produced electronic components,e.g., RFID tags, which might also benefit from the ability toselectively and differentially provide base substrates for each layer,in order to capitalize on substrate characteristics for each layer,separately.

In certain preferred aspects, the transfer substrate is a flexiblesubstrate that is provided as either a flat sheet, or a sheet that iswound into a roll. By providing the transfer substrate as a roll orsheet, one can readily employ commercial roll to roll, or laminate typeprocesses in depositing nanowires onto the receiving substrate.Similarly, the receiving substrate is preferably provided as a flexiblematerial, sheet or substrate, that can be used as a base substrate forthe end application, e.g., as a flexible macroelectronic substrate. Byway of example, FIG. 5 schematically illustrates a process andassociated equipment 500 for depositing and or orienting nanostructureson a receiving substrate surface using a roll-to-roll process. Inparticular, a transfer substrate 502 is provided rolled onto anappropriate drum or roller 504. Similarly, a receiving substrate 506 isprovided upon a second drum or roller 508. The transfer substrateincludes nanostructures disposed upon its surface 510. The receivingsubstrate surface may be pretreated with an adherent material ortreatment or such adherent material may be applied once the receivingsubstrate is un-rolled from the drum, but before it is contacted withthe transfer substrate, e.g., by applicator 512. Applicator 512, maycomprise a spray applicator, a vapor phase applicator, a knifeapplicator, or the like, depending upon the nature of the adherentmaterial used and the desired thickness and/or uniformity of theadherent material coating. Alternatively, in certain preferred aspects,applicator 512 is used to apply an activator to a predisposed materialon the surface of the receiving substrate 506. For example, theapplicator may apply an activation energy to activate chemical groups onthe surface to provide the adherent surface. Alternatively, thereceiving substrate may be provided with a coating of material, e.g., aphotoresist polymer, that can be made adherent through exposure to lightor solvents, e.g., acetone. Such treatments are described in greaterdetail herein.

Following any application and/or activation of an adherent surface onthe receiving substrate, the transfer substrate sheet and receivingsubstrate sheets are passed through feed rollers 514 and 516 and intodrum presses 518, 520 and optionally 522 and 524, whereupon the surfaceof the transfer substrate bearing the nanowires is pressed into contactwith the adherent surface on the receiving substrate. The pressureapplied between the roll presses typically depends upon the nature ofthe nanostructures, the adherent material. Additionally, in some cases,other elements may be applied to the contacting step, including, e.g.,application of heat etc. Following the contacting of the two substratesheets, the laminated sheets are separated into their constituent sheetswith some portion of the nanowires on the transfer substrate surface 510being transferred in whole or in part to the surface of the receivingsubstrate 506. The spent roll of transfer substrate and newly depositedreceiving substrate are then moved to subsequent processing steps, e.g.,rolled onto take-up drums 526 and 528, respectively.

In the case where it is desired to simultaneously deposit and orient thenanostructures on the adherent surface of the receiving substrate, theprocess may be slightly modified by simply moving the transfer substrateroller drums, e.g., feed drum and take-up drum 504 and 526,respectively, at slightly higher or lower speeds from the correspondingfeed and take up drums for the receiving substrate, e.g., drums 508 and528, respectively. The result is that during the contact step, onesubstrate will move faster than the other, causing a stretch or pullalignment of the nanowires disposed between the two substrate's surfacesin the direction of the differential substrate velocity while the wiresare coupled to both substrates.

A wide variety of different materials may be employed as the adherentmaterial on the surface of the receiving substrate. By way ofnon-limiting examples, such adherent materials may comprise materialsthat are coated onto the surface of the receiving substrate, such asthin films of e.g., adherent polymers, or they may comprise surfacetreatments that are applied to the surface of the receiving or othersubstrate to render that surface appropriately adherent. In stillfurther alternate aspects, the adherent material may comprise a surfacederivatization applied to the receiving or other substrate surface toprovide for adherence, e.g., coupling chemical functional groupsdirectly to the surface moieties of the receiving or other substrate, soas to provide adherent characteristics. Finally, in some cases, thesurface of the receiving or other substrate may, in its existing form,e.g., without any modification, provide adherent characteristics.

As noted above, in preferred aspects, polymeric adherent materials areemployed in the invention and are generally applied to the surface ofthe receiving or other substrate as a thin film. Application of thinpolymer films can be accomplished by any of a variety of known methods,including, e.g., spin coating, dip coating, spray coating, lamination,in situ polymerization, etc.

Virtually any polymer adhesive, e.g., contact or pressure sensitiveadhesives, can be applied to the invention depending upon the nature ofthe application to which the ultimate device or article is to be put.However, in certain preferred aspects, polymers that are resistmaterials, e.g., photoresists, are employed as the adherent layer, dueto their ability to be readily patterned onto substrates for selectivedeposition of adherent regions, and for their ability to have theiradherent characteristics modified by optical or chemical means. Examplesof commercially available photoresists that are well suited for theseapplications include, e.g., Shipley S1800, S1813, SPR 220, STR 1000, SPR3000, SPR 3600, SPR 500, SPR 955-CM, Microchem Su-8 and Su8 2000, PMMA,HD Microsystems HD 4000, 4001 and 4010, Clariant AZ1518, AZ4400 andAZ4620, and Dow Cyclotene resists

In alternative aspects, other polymer adhesives may be used as theadherent material, and may be readily provided on the surface of thereceiving substrate. In the case of patterned adherent layers, spincoating methods, inkjet printing methods, screen printing methods orvapor or spray deposition over a physical mask may be used toselectively apply adhesives in desired regions on the surface of thereceiving substrate. Additionally or alternatively, with respect to thephotomask, such adhesives may additionally be UV or otherwisephotocurable, which can allow for ready photopatterning of the adhesiveusing a photomask or other photoexposure system, e.g., laser writing,etc. Such adhesives include a wide variety of adhesive materials thatare readily available from, e.g., 3M, Dow Chemical Corp, Rad-Cure, andthe like.

In addition to composite or polymer adhesive materials, the adherentmaterial on the surface of the receiving substrate may alternativelycomprise a modification of the receiving or other substrate surface,e.g., a rendering the surface soft or “sticky, by virtue of e.g.,softening the surface or attaching chemical groups or derivatizing thesurface to be more adherent coupling chemical moieties to the substratesurface that specifically or nonspecifically bind or otherwise associatewith the nanostructures that are brought into contact or close proximitytherewith (for purposes of the present invention, contact between thenanostructures and an adherent material includes bringing such materialsinto sufficiently close proximity for the nanostructures to bind with orotherwise adherently associate with such moieties, so as to enableadhesion of the structures onto the receiving substrate. Thus, althoughthe adherent material is generally described as a separate layer ofmaterial from the receiving substrate, it will be appreciated that thereceiving substrate may be comprised entirely or substantially of thematerial that functions as the adherent material. For example, a polymersheet for use as the receiving substrate may have an adherent surface,either naturally, or by virtue of chemical, optical or thermaltreatment. In at least one example, a photoresist material, e.g.,polymethylmethacrylate, (PMMA) may be partially softened at the surface,either chemically, through light exposure or by elevating thetemperature at the surface to above the glass transition temperature ofthe polymer, yielding an adherent surface layer of PMMA on an underlyingrigid PMMA receiving substrate.

For solvent treatment, in some cases, it may be useful to use a solventin a vapor phase, so as to be able to better control the solventapplication and facilitate only partially softening of the resist layer(whether it is simply a layer on the substrate or the entire receivingor other substrate). Solvent/polymer combinations are readily known tothose of ordinary skill in the art. For example, for a wide variety ofpolymeric materials, ethyl lactate and ethyl pyruvate are particularlyuseful solvents. Similarly, other organic solvents, such as acetone maygenerally be used, particularly where it is desirable to avoid anyimpact of the solvent on any underlying silicon or silicon oxidematerials, e.g., wires or substrates.

Similarly, where the receiving substrate is comprised of a material witha natural adherent property toward the nanostructures, the surface ofthe receiving substrate may, without modification, provide the adherentmaterial. For example, in the case of silica based nanostructures, e.g.,silicon nanowires, many planar substrates will naturally adhere to thenanowire structures by virtue of Van der Waals interactions. For examplea glass receiving substrate will naturally adhere to nanowires contactedtherewith with very strong adhesion. In accordance with the invention,this surface property is included as the adherent material. The adhesionof nanowire surfaces to other planar surfaces, including glass and othermaterials, is described in detail in U.S. Provisional Patent ApplicationNo. 60/463,766, filed Apr. 17, 2003, which is incorporated herein byreference, in its entirety for all purposes.

In addition to merely depositing nanomaterials onto receivingsubstrates, the processes, systems and compositions described herein arealso useful in depositing substantially oriented nanostructures. As usedherein, the term “substantially oriented” refers to population orsubpopulation of nanostructures that include at least one longer ormajor axis, e.g., the length, that are oriented or aligned so that theirindividual major axes are disposed substantially parallel to a commonaxis, meaning that at least 50% of the nanostructures in a populationare disposed with their major axes disposed within 30° of a common axis,preferably, at least 60% , more preferably, at least 80% and still morepreferably, at least 90% of the nanocrystals are aligned to within 30°of the common axis, preferably, within at least 10° of the common axisand more preferably, at least 5° of the common axis.

Substantial alignment of nanostructures in accordance with theinvention, is generally carried out by a “stick and drag” method or aderivation thereof. In particular, as with the depositing methodsdescribed above, a nanostructure bearing transfer substrate is contactedwith an adherent layer or material on the surface of a receivingsubstrate to adhere the nanostructures to the receiving substrate.However, instead of merely separating the transfer substrate from thenanostructures, the transfer substrate and/or the receiving substrateare moved relative to one another while the nanostructures areeffectively coupled to both. As a result, the nanostructures aretypically pulled into alignment in the direction of motion. As will beappreciated, the effectiveness of the alignment process is increasedwhere the majority of the nanostructures are attached during the processat or near either of the opposing ends of the nanostructure along themajor axis, e.g., nanowires or rods that are attached at one end andextend normally from the transfer substrate such that the opposing endcontacts the adherent portion of the receiving substrate. However, inaccordance with the invention, a desired level of alignment may also beaccomplished with nanostructures that are more randomly arranged on thetransfer substrate, provided that post deposition and alignmentsufficient nanostructures are substantially oriented along the commonaxis, as defined herein.

Once deposited and oriented upon the receiving substrate, the orientedpopulation of nanowires may be subject to additional processing for usein an ultimate application. For example, the adherent material may beremoved from the receiving substrate to leave oriented deposited wireson the receiving substrate. Typically, the adherent material may beremoved by a number of different processes, but will still generallyleave the deposited nanowires in the same position and orientation. Byway of example, particularly where organic adherent materials are used,the receiving substrate may be cleaned of the adherent materialfollowing wire deposition using conventional plasma cleaning techniquesthat are regularly employed in the semiconductor industry. Plasma orother vapor based cleaning based methods are preferred in a number ofcases due to their ability to remove the adherent material withoutphysically disturbing the nanowires adhered thereto.

In alternative aspects, the adherent material may be removed usingsolvent based methods. For example, where a photoresist is employed asthe adherent material, following deposition of nanowires onto theadherent material, the adherent material may be exposed to light torender it soluble in an appropriate developer solution. Usefulphotoresists/developer solution combinations are well known in thesemiconductor industry and are generally readily commercially availablefrom, e.g., Dow, MicroChem, Shipley and the like. In other embodiments,acetone, chlorobenzene, propylene glycolmonomethyl ether acetate(PGMEA), ethyl lactate, ethyl or methyl cellosolve acetate, diglyme, orother industrial solvents in which the adherent material is readilysoluble may be used to remove the adherent material from the receivingsubstrate. Further processes may be employed to remove any residualmaterials, e.g., using isopropanol following acetone treatment, forcertain applications.

Alternatively, the adherent material may be converted to a non-adherentstate, e.g., a photoresist may be soft or hard baked or otherwise cured.Additional layers may be deposited over the nanostructures and/oradditional operational components may be applied to the receivingsubstrate, e.g., oxide layers or other insulators, metal traces orpatterning from electrodes, e.g., source, drain and gate, etc.Additional nanostructures, e.g., deposited and/or oriented may also beapplied over a layer of oriented deposited structures, by either takingadvantage of the existing adherent material or by applying an additionaladherent material over the first layer of nanostructures. Suchstructures may be used as, e.g., diodes, junctions or the like, byapplying different layers of nanostructures, each comprised of adifferent material, in such a way. Using such dual deposition and/ororientation methods, one can create a variety of heterogeneousnanostructure containing devices or systems, wherein separatehomogeneous layers are present.

Examples of additional processing steps include metal deposition overall or portions of aligned populations of nanowires, e.g., to formsource, drain and/or gate electrodes for nanowire based transistors,diodes, etc. Insulating layers may be integral to the depositednanowires or they may be separately deposited over nanowires. A varietyof other uses and processes for these nanowire populations are describedin, e.g., WO 02/080280, WO 02/17362, and U.S. Ser. No. 60/414,359, filedSep. 30, 2002, and U.S. Ser. No. 60/474,065, filed May 29, 2003, thedisclosures of which are hereby incorporated herein by reference intheir entirety for all purposes.

EXAMPLES

The methods described herein were employed in depositing nanowires ontoa substrate in a substantially aligned orientation. In particular, a 4″silicon wafer was used as the receiving substrate and patterned with asolution of a pressure sensitive adhesive (PolySciences 534028 in 30%isopropanol) with spots of adhesive that measured approximately 50 μm indiameter. Spotting was carried out using a standard XYZ robot andpipettor. Once deposited, the spots were dried at 60° C. to formadhesive pads about 10 μm thick on the surface of the wafer.

The transfer substrate was prepared on another 4″ silicon wafer usingthe standard gold colloid based CVD growth process as generallydescribed by Lieber et al. (See, e.g., US 2003-0089899-A1). Theresultant transfer wafer possessed a covering of nanowires that eachgenerally measured approximately 40 nm in diameter and 40 μm in length(as approximated from SEM inspection).

The wire surface of the transfer wafer was set down upon the adhesivepad bearing surface of the receiving wafer substrate such that thenanowires contacted the adhesive pads, without any additional appliedpressure. The receiving and transfer wafers were then sheared inopposite directions an aggregate distance of 1 mm and the wafers wereseparated.

The receiving substrate was then placed into a plasma cleaner to removeany organic material on the substrate, including any adhesive. Oncecleaned, the receiving substrate was then analyzed by SEM. FIG. 6 is animage from the SEM of oriented nanowires remaining fixed in the locationof a removed adhesive pad following cleaning.

While the foregoing invention has been described in some detail forpurposes of clarity and understanding, it will be clear to one skilledin the art from a reading of this disclosure that various changes inform and detail can be made without departing from the true scope of theinvention. For example, all the techniques and apparatus described abovecan be used in various combinations. All publications, patents, patentapplications, and/or other documents cited in this application areincorporated by reference in their entirety for all purposes to the sameextent as if each individual publication, patent, patent application,and/or other document were individually indicated to be incorporated byreference for all purposes.

1. A method of depositing nanomaterials onto a substrate, comprising:providing a plurality of nanostructures disposed upon a transfersubstrate; providing an adherent material deposited on one or moreselected regions of a receiving substrate; mating the transfer substratewith the receiving substrate, whereupon the nanostructures contact thenanostructures on the transfer substrate with the one or more selectedregions of the receiving substrate; and separating the transfersubstrate from the receiving substrate to leave a population ofnanostructures adhered to the one or more selected regions of thereceiving substrate.
 2. The method of claim 1, wherein the plurality ofnanostructures comprises a plurality of nanofibers.
 3. The method ofclaim 2, wherein the plurality of nanofibers comprises a plurality ofsemiconductor nanowires.
 4. The method of claim 3, wherein the pluralityof semiconductor nanowires comprise a semiconductor material selectedfrom a Group II-VI semiconductor, a Group Ill-V semiconductor, or aGroup IV semiconductor.
 5. The method of claim 1, wherein thenanostructures are synthesized on the transfer substrate.
 6. The methodof claim 1, wherein the nanostructures are deposited upon the transfersubstrate.
 7. The method of claim 1, wherein the mating step comprisespressing the transfer substrate to the selected regions of the receivingsubstrate.
 8. The method of claim 1, wherein the transfer substratecomprises a flexible planar sheet substrate.
 9. The method of claim 8,wherein the transfer substrate is disposed on a roll.
 10. The method ofclaim 9, wherein the roll of the transfer substrate is rolled over thereceiving substrate.
 11. The method of claim 1, wherein the receivingsubstrate comprises a flexible planar sheet substrate.
 12. The method ofclaim 11, wherein the receiving substrate is disposed on a roll.
 13. Themethod of claim 1, wherein between the mating step and the separatingstep, at least one of the transfer substrate and the receiving substrateare moved in a direction substantially parallel relative to the other ofthe transfer substrate and the receiving substrate, to substantiallyalign the nanostructures adhered to the receiving substrate.
 14. Themethod of claim 13, wherein at least 50% of nanostructures in thepopulation of nanostructures adhered to the one or more selected regionsof the receiving substrate are aligned to within less than 30° of acommon axis.
 15. The method of claim 13, wherein at least 50% ofnanostructures in the population of nanostructures adhered to thereceiving substrate are aligned to within less than 10° of a commonaxis.
 16. The method of claim 13, wherein at least 50% of nanostructuresin the population of nanostructures adhered to the receiving substrateare aligned to within less than 5° of a common axis.
 17. The method ofclaim 13, wherein at least 80% of nanostructures in the population ofnanostructures adhered to the one or more selected regions of thereceiving substrate are aligned to within less than 30° of a commonaxis.
 18. The method of claim 13, wherein at least 80% of nanostructuresin the population of nanostructures adhered to the one or more selectedregions of the receiving substrate are aligned to within less than 10°of a common axis.
 19. The method of claim 13, wherein at least 90% ofnanostructures in the population of nanostructures adhered to the one ormore selected regions of the receiving substrate are aligned to withinless than 30° of a common axis.
 20. The method of claim 13, wherein atleast 90% of nanostructures in the population of nanostructures adheredto the receiving substrate are aligned to within less than 10° of acommon axis.
 21. The method of claim 1, wherein following the separatingstep, the adherent material is removed from the surface of the receivingsubstrate.
 22. The method of claim 21, wherein the removing stepcomprises plasma cleaning of the receiving substrate.
 23. The method ofclaim 21, wherein the removing step comprises cleaning the surface ofthe receiving substrate with a solvent.
 24. The method of claim 21,wherein the adherent material comprises a photoresist, and the removingstep comprises exposing the adherent material to light and contactingthe adherent material with a developer solution.
 25. A method ofdepositing a plurality of substantially oriented nanostructures on asubstrate, comprising: providing a transfer substrate having a pluralityof nanostructures deposited thereon, each of the plurality ofnanostructures having a major axis; providing a receiving substratehaving a surface comprising an adherent material; bringing thenanostructures on the surface of the transfer substrate into contactwith the adherent material on the surface of the receiving substratewhereupon the nanostructures adhere to the adherent material; moving oneor more of the transfer substrate and receiving substrate relative tothe other of the transfer substrate and the receiving substrate tosubstantially orient the nanostructures along a common axis; andseparating the nanostructures from the transfer substrate after themoving step, to leave the plurality of nanostructures substantiallyoriented on the receiving substrate along the common axis.
 26. Themethod of claim 25, wherein a majority of the nanostructures aredeposited on the transfer substrate with the major axis beingsubstantially normal to a plane of the surface of the nanostructures onthe transfer.
 27. An article, comprising: a substrate having a firstsurface; a polymeric adherent material disposed on the first surface;and a plurality of nanostructures each comprising a major axis, disposedon the first surface, and adhered to the adherent material, theplurality of nanostructures being substantially oriented along a commonaxis.
 28. The article of claim 27, wherein at least 50% of the pluralityof nanostructures are oriented to within 30° of the common axis.
 29. Thearticle of claim 27, wherein at least 50% of the plurality ofnanostructures are oriented to within 10° of the common axis.
 30. Thearticle of claim 27, wherein at least 50% of the plurality ofnanostructures are oriented to within 5° of the common axis.
 31. Thearticle of claim 27, wherein at least 60% of the plurality ofnanostructures are oriented to within 30° of the common axis.
 32. Thearticle of claim 27, wherein at least 60% of the plurality ofnanostructures are oriented to within 10° of the common axis.
 33. Thearticle of claim 27, wherein at least 60% of the plurality ofnanostructures are oriented to within 5° of the common axis.
 34. Thearticle of claim 27, wherein at least 80% of the plurality ofnanostructures are oriented to within 30° of the common axis.
 35. Thearticle of claim 27, wherein at least 80% of the plurality ofnanostructures are oriented to within 10° of the common axis.
 36. Thearticle of claim 27, wherein at least 80% of the plurality ofnanostructures are oriented to within 5° of the common axis.
 37. Thearticle of claim 27, wherein at least 90% of the plurality ofnanostructures are oriented to within 30° of the common axis.
 38. Thearticle of claim 27, wherein at least 90% of the plurality ofnanostructures are oriented to within 10° of the common axis.
 39. Thearticle of claim 27, wherein at least 90% of the plurality ofnanostructures are oriented to within 5° of the common axis.
 40. Thearticle of claim 27, wherein the polymeric adherent material comprises aresist.
 41. The article of claim 40, wherein the resist comprises aphotoresist.
 42. The article of claim 27, wherein the adherent materialand the nanostructures adhered to the adherent material are disposedupon selected portions of the first surface.
 43. A composition,comprising: a layer of adherent material; and a plurality ofsubstantially aligned nanowires adhered to a surface of the adherentlayer.
 44. The composition of claim 43, wherein at least 50% of theplurality of nanostructures are oriented to within 30° of a common axis.45. The composition of claim 43, wherein at least 50% of the pluralityof nanostructures are oriented to within 10° of a common axis.
 46. Thearticle of claim 43, wherein at least 50% of the plurality ofnanostructures are oriented to within 5° of a common axis.
 47. Thearticle of claim 43, wherein at least 60% of the plurality ofnanostructures are oriented to within 30° of a common axis.
 48. Thearticle of claim 43, wherein at least 60% of the plurality ofnanostructures are oriented to within 10° of a common axis.
 49. Thearticle of claim 43, wherein at least 60% of the plurality ofnanostructures are oriented to within 5° of a common axis.
 50. Thearticle of claim 43, wherein at least 80% of the plurality ofnanostructures are oriented to within 30° of a common axis.
 51. Thearticle of claim 43, wherein at least 80% of the plurality ofnanostructures are oriented to within 10° of a common axis.
 52. Thearticle of claim 43, wherein at least 80% of the plurality ofnanostructures are oriented to within 5° of a common axis.
 53. Thearticle of claim 43, wherein at least 90% of the plurality ofnanostructures are oriented to within 30° of a common axis.
 54. Thearticle of claim 43, wherein at least 90% of the plurality ofnanostructures are oriented to within 10° of a common axis.
 55. Thearticle of claim 43, wherein at least 90% of the plurality ofnanostructures are oriented to within 5° of a common axis.
 56. A system,comprising: a transfer substrate having a plurality of nanostructuresdisposed upon a first surface thereof; a receiving substrate comprisinga first surface disposed opposed to the first surface of the transfersubstrate; and, an automatable translation system coupled to at leastone of the transfer substrate and the receiving substrate, for bringingthe first surface of the transfer substrate and the first surface of thereceiving substrate into contact with each other and subsequentlyseparating the first surface of the transfer substrate from the firstsurface of the receiving substrate.
 57. The system of claim 56, whereinthe translation system comprises one or more rollers for directing asheet of the transfer substrate into contact with a sheet of thereceiving substrate.
 58. The system of claim 56, further comprising anadherent material deposition system disposed over the first surface ofthe receiving substrate to deposit adherent material thereon, prior tothe translation system moving the first surface of the transfersubstrate into contact with the first surface of the receivingsubstrate.